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Table 2 Comparison of clinical characteristics and outcomes in 175 probable iNPH patients using different prognostic tests

From: The Kuopio idiopathic normal pressure hydrocephalus protocol: initial outcome of 175 patients

Variables Tap positive, infusion test not performed
n = 98
Tap negative, infusion test not performed
n = 29
Tap negative, infusion test positive
n = 34
Tap negative, infusion test negative
n = 14
Test statistics (df) Test of strength p value
Number of participants % Number of observations if any missing data Number of participants % Number of observations if any missing data Number of participants % Number of observations if any missing data Number of participants % Number of observations if any missing data
Outcome
 Favorable clinical outcome 3 months postoperatively (yes) 83 85   26 93 28 28 82   11 79   2.23 (3)   0.527a
 Walking speed improvement 3 months postoperatively (yes) 55 75 73 14 58 24 12 41 29 4 36 11 10.72 (3) 0.32c 0.003 b
 Favorable INPHGS outcome 3 months postoperatively (yes) 41 48 86 10 43 23 11 36 31 7 70 10 3.86 (3)   0.278b
 Favorable HRQoL outcome 3 months postoperatively (yes) 31 52 59 7 54 13 14 67 21 3 43 7 1.75 (3)   0.626a
Characteristics
 Age (at referral to the neurosurgical department) 74.3f 6.9g   73.5f 6.1g   74.1f 7.3g   72.4f 9.2g   0.66   0.882d
 Sex (female) 43 44   13 45   18 53   8 64   2.58 (3)   0.460b
INPH related symptoms
 Impairment of gait 98 100   28 97   32 94   13 93   7.02 (3)   0.071a
 Urinary incontinence or urge 80 82   23 79   26 76   14 100   3.87 (3)   0.276a
 Impaired cognition 79 81   27 93   28 82   13 93   4.04 (3)   0.257b
 Full triad 65 66   21 72   21 62   12 86   3.01 (3)   0.390b
 Onset of iNPH related symtoms              4.05 (3)   0.256b
 Onset a year or less from the referral 35 36 95 7 24   15 46 33 7 50     
 Onset more than a year from the referral 60 64 95 22 76   18 54 33 7 50     
First symptom of iNPH
 Impairment of gait or imbalance 54 55   17 59   9 27   7 50   9.41 (3) 0.23c 0.024b
 Cognition impairment 21 21   6 21   11 32   6 43   4.03 (3)   0.258a
 Vertigo 10 10   0 0   7 21   1 7   9.59 (3) 0.21c 0.022a
 Urinary incontinence or urge 8 8   3 10   3 9   0 0   2.57 (3)   0.463a
 Other 5 5   3 10   3 9   0 0   3.09 (3)   0.379a
Severity of INPH related symptoms preoperatively
 INPHGS total score (0–12) 6.1f 2.6g 94 5.9f 2.8g   5.6f 2.8g   6.7f 2.6g 13 1.80   0.614d
 Cognition impairment (MMSE score, 0–30) 22.0f 4.9g   22.9f 4.2g   22.5f 4.5g   23.1f 3.1g 13 0.73   0.865d
Comorbidity
 Presence of Aβ or HPτ found in the frontal cortical biopsy 56 60 93 9 34 26 17 55 31 5 45 11 5.71 (3)   0.126b
 Surgical complications 9h 9   5i 17   1j 3   1k 7     0.259a
  1. iNPH Idiopathic normal pressure hydrocephalus, iNPHGS iNPH Grading Scale, MMSE Mini-Mental State Examination, amyloid-beta, HPτ hyperphosphorylated tau
  2. Statistically significant difference (Bonferroni correction, p < 0.0025) is italic
  3. aMaximum likelyhoodratio Chi square test
  4. bPearson Chi square test
  5. cCramer’s V
  6. dIntependent-Samples Kruskal–Wallis Test
  7. fmean value
  8. gstandard deviation
  9. h2 acute subdural hematomas caused by post-operative falling, 2 chronic subdural hematomas, 1 ventricular catheter displacement, 2 shunt infections, 1 peritoneal catheter displacement, 1 intracerebral hemorrhage
  10. i3 chronic subdural hematoma, 2 shunt infections
  11. j1 peritoneal catheter displacement
  12. k1 peritoneal catheter displacement. Strength statistics were reported only for the statistically significant group differences